With development of a 3G/4G communications technology, higher-order modulation multi-carrier transmitters are widely applied to a 3G/4G network. A power radio frequency amplifier is designed to have highest power consumption in a transmitter, is one of most important components, and determines reliability and heat consumption of a base station. Therefore, much attention needs to be paid to the power radio frequency amplifier.
At present, there are many types of transmitters on the market. A structure of a single-input multi-band transmitter is shown in FIG. 1, including: DPD (digital pre-distortion, digital pre-distortion) components, DUC (digital up-conversion, digital up-conversion) components, an adder, a DAC (digital-analog convertor, digital-to-analog converter), AQM (analog quadrate modulation, analog quadrate modulation) components, and a single-input dual-band PA (power amplifier, power amplifier). A basic structure of a multi-input single-band transmitter is shown in FIG. 2, including: a DPD component, a signal decomposition circuit, DACs, AQM, and a dual-input single-band PA. A dual-input dual-band PA may be considered as a dual-input single-band PA when independently transmitting a signal in one band.
In the prior art, a dual-input dual-band PA has a problem of selecting a decomposition path, because for the dual-input dual-band PA, one output may have multiple corresponding input signal combinations. That is, there are different paths for one output, and different paths have different impact on performance of the PA. When the dual-input dual-band PA is used as a dual-input single-band PA (an optimal decomposition path when a signal in one band is independently transmitted), because two bands are different, a transmit signal in the other band directly affects efficiency of the power amplifier in the band and the like.
As can be learned, when a dual-input dual-band PA transmits signals in bands concurrently, how to enable the power amplifier to work normally and maintain relatively high efficiency is a problem that currently needs to be resolved.